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                Neerc2011 Lanes                </h1>
                <p>时间限制：10s&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;  空间限制：64MB</p>			</div>
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                                <h3>题目描述</h3><p><div>某座大桥上有n1条从左至右的车道，n2(n1,n2&le;10)</div>
<div>条从右至左的车道，还有一条潮汐车道。</div>
<div>在早上从左向右行驶的车辆较多，潮汐车道的方向是</div>
<div>从左向右；晚上正好相反。</div>
<div>也就是说早上有n1+1条左右车道，n2条右左车道；晚</div>
<div>上有n1条左右车道，n2+1条右左车道。</div>
<div>交通是很复杂的问题，我们有如下的抽象模型：</div>
<div>从早到晚被分为m(m&le;100000)个离散的时刻，编号从1开始。</div>
<div>在每个时刻，两侧均有一些车抵达。</div>
<div>设左右车道和右左车道各有L,R条车道，那么左侧通行L辆车</div>
<div>（即减少L辆车），右侧通行R辆车。</div>
<div>剩下的车等待下一时刻。</div>
<div>如果在时刻m后仍有车辆在等待，那么后面的时刻仍按同样模</div>
<div>型进行，只是不会有新到达的车辆了。</div>
<div>你的任务是决定在哪一时刻改变潮汐车道的方向，能</div>
<div>使所有车辆等待时间的总和最小化。</div>
<div>不过潮汐车道也不是瞬间就能改变方向的，它需要r</div>
<div>个时刻来改变方向。也就是说，如果在t时刻改变方向，那么在[t,t+r-1]</div>
<div>时刻内潮汐车道不能使用，即左右和右左车道各有n1和n2条。</div>
<p></p></p><hr/><h3>输入格式</h3><p></p><hr/><h3>输出格式</h3><p></p><hr/><h3>样例输入</h3><pre>2 2 10 2
1 0
2 1
3 2
4 2
3 3
2 3
1 5
0 3
1 2
0 1
</pre><hr/><h3>样例输出</h3><pre>4</pre><hr/><h3>提示</h3><p>没有写明提示</p><hr/><h3>题目来源</h3><p>没有写明来源</p>
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